Rivet setting machine



Nov. 17, 1931. F. R. ALFORD RIVET SETTING MACHINE Filed 001:. 4, 1929 3 Sheets-Sheet l INVEIJTOR \qkm%1/?197Z m2 BY J? 6 6ATTORNEY.

Sheets-Sheet 2 Filed Oct. 4. 1929 Fig.3

INVENTOR @a/nfilsifma BY zz z M ATTORNEY Nov. 17, 1931.

F. R. ALFORD RIVET SETTING MACHINE Filed Oct. 4, 1929 5 Sheets-Sheet 3 FNVENTOR ATTORNEY.

Patented Nov. 17, 1931 UNITED STATES PATENT OFFICE FRANK R. ALFORD, OF BRISTOL, CONNECTICUT, ASSIGNOR TO ATLAS TACK CORPORA- A 'IION, OF FAIRHAVEN, MASSACHUSETTS, .A CORPORATION OF NEW YORK RIVET SETTING MACHINE Application filed October 4, 1929. Serial No. 397,312.

i invention relates to improvements in rivet setting machines and more partlcularly vto machines of the type that 1s adapted toopcrate automatically to set or apply a tubular or bifurcated rivet for each actuation of a control member of the machine.

An object of the invention is to provide a tion of the rivets to articles of work of various shapes and sizes at various heights and in different positions.

A further object of the invention is the provision in a rivet setting machine of the character described of an improved mounting for the rivet setting head of the machine, provision being made therein to permit the head to yield should a solid rivet or other obstruction get between the rivet setting tools of the machine, whereby breakage of the tools or associate parts of the machine will be obviated and easy removal of the obstruction permitted.

A further object of the invention is the provision in a machine of the character described of an improved rivet setting spindle and an improved actuating mechanism therefor, including clutch means adapted to prevent repeating ofthe rivet setting mechanism after a single actuation of the machine control member and also adapted to permit the direction of movement of the spindle actuating mechanism to be reversed by manual action when desired to facilitate adjustment of the rivet setting tools, removal of rivets that are out of place, or for any other useful purpose.

Other objects of the invention relate to features of construction and operation of com ponent parts of the improved machine, which features together with advantages and beneficial results of the uses thereof will appear A from the following description of a practical embodiment of the invention.

In the accompanying drawings:

Figure 1 is a front elevation of a rivet set-. ting machine embodying the'invention;

Fig. 2 is a side elevation of the improved machine, with portions thereof broken away and other portions shown in section Fig. 3 is a fragmentary relatively enlarged. side elevation of the head portion of the machine, parts being broken away to show clutch means and an associated controlmember for connecting and disconnecting the rivet setting spindle actuating mechanism with and from a continuously rotating pulley-fly wheel at each actuation of the control member.

Fig. 4 is a section substantially along the line 4 l: of Fig. 3, looking in the direction of the arrows; v

Fig. 5 is a relatively enlarged fragmentary front elevation of the head portion of the machine;

Fig. 6 is a perspective view of the rivet setting spindle unit assembly together with cer-.

tain associated parts; and

Fig. 7 is a fragmentary plan sectional view, showing details of the clutch bolt and its control member, parts being broken away.

The machine illustrated in the drawings comprises a basal having three spaced supporting feet 2- and having in itsupper part a vertical socket 3 in which-is swiveled the reduced lower end portion 4 of a tubular column 5. The latter may be substantially square or rectangular in cross-sectional configuration. A set screw 6 threaded through an opening in the base 1 projects into an annular groove 7 in the reduced lower end portion of the column 5 and prevents accidental vertical displacement of the column from the base. The set screw 6 may be tightened to prevent the column from turning in the base angularly about its axis from any adjusted position.

The top of the column 5 is provided with a fiat supporting surface on which rests the fiat bottom surface of the lower end portion 8 of the head 9 of the frame structure of the machine. The contacting portions of the column and the head of such frame structure may be enlarged somewhat laterally at both sides thereof, as shown in Fig. 5, to assure firm support of the head on the column. The head 9 is located on the colunm in a position that is determined by fore-and-aft keys 10 and a transverse key 11 so as to be capable of limited movement on the column about the axis of the key 11, the adjacent surfaces of the head and the column at the rear of the key 11 being beveled away from each other as indicated at 12 in Fig. 3 to permit such rocking movement of the head. To this end, the fore and-aft keys 10 preferably are rectangu ar in cross-section and are secured with their lower portions in grooves 13 which extend fore-andaft of the top of the column so that the upper portions of such keys will have a rather snug, though not tight, fit in a registering groove or grooves 14 in the bottom of the head 9. l The key 11 preferably is circular in cross-sectional configuration and is secured with a substantially longitudinal half portion thereof in a semi-circular transverse slot 15 in the top of the column while the remaining semi-circular longitudinal half portion of such :ey fits in a correspondingly configured transverse groove 16 in the bottom of the head. Four spaced studs 17 project from the top of the column through openings 18 in the lower portion 8 of the head 9. Compression springs 19 are disposed on the protruding upper end portions of the studs between adjust: ing nuts 20 and the adjacent portions of the head 9, and tend to hold the head firmly although yieldingly down on the top of the column. The openings 18 are somewhat larger than the portions of the studs 17 that extend therethrough, so that the head may rock anti-frictionally on the combined key and bearing member 11 against the action of the springs 19 in response to an upward stress on the front portion of the head, which stress may occur should a solid rivet, a portion of the work to be riveted or other obstruction get between the riveting tools. However, the head always will be prevented from becoming displaced in a fore-and-aft or lateral direction on the column and will be returned'to the desired horizontal position on the column by the springs and gravity when the above mentioned upward stress has been removed. It is obvious that various arrangements of spring or other resilient connections between the head and the column maybe provided in lieu of the particular construction which is illustrated in the drawings and has just been described in detail. For example, one or more of the studs may be carried by the head instead of by the column, and spring means may be provided on such studs below the upper part of the column rather than above the lower portion of the head.

The front side of the column 5 is provided with a vertical slot 21, Fig.1. A forwardly extending bracket 22 has at its rearward side a vertical tongue or reduced portion 23 which fits snugly although slidably in the slot- 21. The inner face of the front wall of the column is provided with a vertical series of notches or teeth 24 adjacent to the slot 21. A screw 25 extends from the interior of the column through the slot 21 and threadedly engages an opening 26 in the rearward portion of the bracket 22. A washer 27 on the screw 25 between the head of the latter and the inner face of the front wall of the column has teeth adapted to mesh with the teeth 2% on the interior of the column when the screw has been tightened, thereby securing the bracket 2:2 firmly to the column.

The position of the bracket 22 on the column may be adjusted vertically by merely loosening the screw 25 until the washer 27 will slide along the teeth 24 as the bracket moves along the slot 21. Apertures, as 28 in the side walls of the column, permit easy access to the head of the screw 25 to permit vertical adjustment of the bracket along the column. The adjustable means just de' scribed for securing the bracket to the column permits a finer and more accurate vertical adjustment of the bracket on the column within a longer range and in a more facile and convenient manner than has been possible in any prior rivet setting machine known to me. Moreover, unsightly openings to be used selectively for screws for fastening the bracket to the column, are obviated by the use of my improved adjustable bracket securing construction.

The bracket 22 carries a removable post or adaptor 29 which carries a removable and replaceable anvil 30 provided with a pilot pin 31. In the operation of setting a tubular or bifurcated rivet, the lower end of the rivet is projected downwardly through a prepared opening in the work over the pilot pin, and is guided by the latter against the anvil, which due to its shape, curls the rivet backward against the work as the rivet is driven downward from above by a driver which will be hereinafter described. The anvil, pilot pin and incidental tools necessary for the riveting of different kinds of work may be changed as required to meet various service conditions.

The front end portion of the head 9 carries a rivet race block 32 on which is supported a hopper 33 and a rivet feeding device 34 for feeding continuous series of rivets, with their shanks turned outward, downwardly along the rivet race 35 against a horizontally slidable rivet feed plate 36. A pair of rivet supporting spring aws 37 are suspended from a carrier 38 that is slidable vertically in a guideway 39 in the rivet race block assembly.

A spring 40, connected at one end to a sta tionary part, as to a pin ll'OIl the race block,

lZO

and its other end with a'portion42 of the jaw carrier, tends to retain the jaws yield ingly in their raised position as shown in Fig. 5. A pin 43 that is carried by the vertically slidable jaw carrier projects through a slot 44 in a wall of the rivet race block assembly. A removable and replaceable stop piece 45 in the lower part of the slot 44 limits the downward movement of the jaws. Stop pieces 45 of different lengths may be used selectively to adjust the lower limit to different heights. A vertically adjustable stop piece 46 in the upper part of the slot 44 provides an adjustable upper limit for the vertical movement of the jaws.

Each time the rivet feed plate 36 is slid to the left from the position shown in Figs. 2 and 3 against the action of the spring 47, the lowermost rivet in the race is permitted to move therefrom into the final delivery slot 48 against the lower end portion of a driver 49, Fig. 5, which then is in a downwardly projected or driving position. When the driver is raised, the rivet is permitted to fall,

5 shank downwardly, between the-jaws 37 which engage under the head of the rivet and thus support it above and in axial alignment with the pilot pin 31 on the anvil 30. The rivets thus are fed one at a time and in rapid succession downwardly between the jaws 37.

A bell crank lever 50 is pivotally supported on a pivot pin 51 on the race block and has a spring extension 52 on one arm thereof. This spring extension projects through a vertical slot 53 in the rivet feed plate 36 so that swinging movement of the bell crank lever in a clockwise direction about the axis of the pivot element 51 from the position shown in Fig. 3 will effect the aforesaid rivet feeding movement of the plate 36 to the left from the position shown in Fig. 3. A cam roll 54 on the upper arm of the bell crank lever 50 will be engaged by a cam surface 55 on a downwardly moving vertically slidable yoke or block 56, Fig. 6, when the driver 49 moves downward on its working stroke.

Thus, each downward or working stroke of the driver will be attended by rivet feeding movement of the plate 36 while the upward or retractive stroke of the driver will be attended by a spring actuated return of the vertical bearing 57in the race block to move the lower end thereof to and from a rivet driving position between the rivet holding jaws. The lower end of the driver is adapted to drive the rivet downwardly over the pilot against the anvil. The upper end of the driver 49 fits in a vertical bore or socket in the lower part ofthe yoke 56 and is removably secured in place therein, as my a screw 58, so as to be substantially rigid with the yoke. An upper guide 59 extends slidably through a vertical bearing 60 in the upper portion of the race block substantially in axial alignment with the driver 49. The lower end portion of the guide 59 is secured removably in a vertical bore or socket in the upper portion of the yoke 56. A screw 61 may be employed for this purpose. It thus will be apparent. that the invention provides a strong and durable driver assembly or socalled spindle of simple construction, any part of which can be readily removed and replaced without replacement of the other parts, should such-action be required or desirable for any reason. It may be desirable at timesto use drivers having specifically different lower endportions at different times according'to different service. requirements. In all prior rivet setting machines of which I am aware, the spindle has comprised but a single one-piece member having a lower end portion adapted to hold relatively small intercl'iangeable tools to suit the heads of the rivets to be driven; Such interchangeable tools are difiicult to handle and are likely to be displaced or broken as a result of the shock resulting from the operations of-the machine. The improved driver assembly of the present invention possesses relatively great strength, rigidity and durability and permits easy and convenient replacement of any part thereof should such replacement be required.

A block 62 is mounted to slide in a transverse uideway 63 in the yoke 56. A pin 64 on a crank arm 65 is journaled in the slide block 62. The crank arm 65 is secured removably to a crank shaft 66 and as the crank shaft rotates about its axis, the driver assembly will be reciprocatedvertically as a unit. By using crank arms of different lengths at different times, the amplitude of the vertical movements of the driver can be changed to meet particular service require ments, as to drive rivets of different lengths at different times. Also, the crank arm, being separate from the crank shaft, can be removed and replaced readily and cheaply should such action be required or desirable, as because of wear or damage thereto, without replacement of the crank shaft being required. I i As hasbeen hereinbefore stated, the vertical movements of the cam surface on the driver yoke control the rivet feeding opera-- tions of the plate 36.

The yoke 56 is connected by a link 67 with one arm 68 of a bell crank lever 69 that is fulcrumed on a pivot shaft 70 that extends 'pivotally of the rivet feeding device 34. The

other arm, 71, of' the bell crank lever 69 carries a pivot pin 72 on which a pawl 73 is pivotally mounted in position to swing by gravity into engagement with the teeth of a ratchet wheel 74 that is secured to the shaft 7.0. When the driver moves downward on swung counterclockwise from the position shown in Fig. 3, the pawl riding idly over the ratchet teeth. On the return or upward movement of the driver, the clockwise movement of the bell crank 69 with the pawl engaged with a tooth of the ratchet wheel will cause a rotary movement of the shaft 70 in a clockwise direction.

The shaft thus will be given an intermittent rotary movement as the driver assembly reciprocates and it will be understood that such rotation of the shaft will effect a like movement of av rotary part of the mech anism for feeding rivets into the rivet race 35, which mechanism may be of generally conventional or any suitable known construction. In order to limit the swinging movement of the pawl away from the ratchet wheel and to prevent the pawl from swinging beyond a position from which gravity will move it into engagement with the ratchet wheel on the upward movement of the driver, a pin is provided on a tail piece 76 of the pawl for engaging with the bell crank arm 71. This feature is novel in the improved rivet setting machine of the present invention, and assures reliability and uniformity of action of the intermittent driving mechanism for the rivet feeding device.

During part of the downward or driving stroke of the driver, the rivet supporting jaws will move downward with the driver against the action of the springs 40. The

piws will be sprung apart to release the rivet as the driver completes its downward stroke so that the rivet head may be driven firmly against the work.

The crank shaft 66 is journaled in spaced bearings 77 which are provided on the head 5). These bearings preferably are provided with removable cap sections 78 and with lubricant wells 7 9 having felt lubricant pads, whereby dust and other foreign matter are eifectually excluded from the hearings and adequate lubrication can be effected and maintained by replenishing the lubricant supply at intervals of relatively long duration.

The crank shaft has a slightly reduced projecting end portion 66a on which is loose- 1y mounted the hub 80 of a combination pulley and fly wheel 81, the rim of which is formed with an annular groove 82 and is of sufficient bulk and weight to assure the desired momentum to adapt the machine for relatively heavy work. A retaining plate 83 secured to the outer end of the crank shaft and a shoulder 84 at the inner end of the reduced end portion 66a of the crank shaft serve to prevent any appreciable axial movement of the pulley-fly wheel on the crank shaft while permitting its removal and replacement when required.

A belt 85 extends around the grooved rim li v l portion of the pulley-fly wheel and around the drive pulley 86 of a motor 87 which may be mounted on a bracket 88 on the column 5, whereby the pulley-fly wheel will be rotated continuously when the motor is operating.

clutch is provided under the control of a. pivoted so-called clutch stripper or control member, whereby on each actuation or tripping of the control member, the pulleyfly wheel will be operatively connected with the crank shaft so that the latter will be rotated for the time required to effect one complete riveting operation, that is, the driving and securing in place of one rivet and the return of the moving rivet applying and feed controlling parts to proper positions to initiate another riveting operation on the succeeding actuation of the clutch control member. In order to stop the movement of the moving rivet applying parts at such proper places after the crank shaft has been de-clutched from the pulley-fly wheel and to prevent the riveting operation from being repeated after such de-clutching, a braking force is applied continuously to the crank shaft. To this end, the portion of the crank shaft that extends between the bearings may have a brake drum 89 secured thereon.

A brake band 90 extends around the brake drum and has one of its ends secured firmly, as at 91, Fig. 5, to the head 9 while its other end is secured to the upper end of a bolt 92 which extends slidably through a vertical opening in a laterally projecting portion 9 3 of the head, such bolt being urged continuously downward by a spring that encircles the bolt between the part 93 and a nut ill on the lower end of the bolt, whereby an adjustable friction is continuously applied to the brake drum.

The clutch mechanism comprises a clutch collar 95 secured to the crank shaft adjacent to the inner end of the hub of the pulleyfiy wheel, Fig. 3. This clutch collar is provided with a. longitudinally extending external guideway 96a in which a longitudinal 1y slidable clutch or so-called shoot bolt 96 is slidably mounted. A transverse pin 97 carried by the clutch collar has a portion extending across a longitudinal cut-away portion 98 of the inner side of the clutch bolt and serves to limit the longitudinal. movements of the latter on the clutch collar. A spring 99 tends to urge the clutch bolt toward tl c pulley-fly wheel. A protective and dust 0X- eluding ring 100 may be secured on the inner end portion of the hub of the pulley-iiy wheel so as to extend in overlapping relation with the clutch collar and clutch bolt.

The hub of the pulley-fly wheel is provided with a pair of diametrically opposite inserts 101 of relatively hard metal or material. These inserts extend from the inner end of the hub part way through the latter, and openings, as at 102, preferably are provided rangement provides shoulders 105 on the inner end of the hub. The clutch bolt 96 has a flattened or cut-away lateral contact face 106 adapted to contact with the lateral face 104 of the projecting end of the insert first engaged therewith when the clutch bolt is projected by its spring against the adjacent end of the pulley-fly wheel. The pulley fiy wheel and crank shaft then will rotate together so long as the clutch bolt remains in projected position. When the clutch bolt is retracted, the driving connection between thepulleyfly wheel and the crank shaft will be broken.

A control member or so-called clutch stripper operable in a certain manner to retract the clutch bolt from its projected position and to retain it thus retracted and also operable in another manner to permit the projection of the clutch bolt will now be described. Such control member comprises an arm 107 mounted at one end on a pivot element 108, Fig. 1, that extends parallel with the crank shaft so that a concavely curved portion 107a of such arm is located below and adjacent to the clutch collar. The pivot element 108 may be carried by the arm 109 of a bracket 109a that is secured to the head 9. A tensile spring 110 tends to pull the arm 107 upwardly toward the clutch collar and against a stop screw 111 that may be carried by an upper portion 112 of the bracket arm 109. The stop screw 111 "preferably is ad justed so that the arm 107 is never permitted to ride on the clutch collar,thus obviating wear on the arm and the collar as well as cutting of the latter.

A lower stop screw 113 carried by the bracketarm 109 limitsthe downward swinging movement of the arm 107 against the action of the spring 110. The arrangement is such that a lateral cam surface 114 on the portion 107a of the control arm will contact with a side wall ofa transverse slot 115 in of the portion 107a will be sufliciently elevated to enter the slot 115 of the clutch bolt as the control member starts to swing upward, thereby guiding the 'control member into camming relation with the clutchbolt and assuring uniformity of action of the clutch bolt retracting and control member, and obviating the objectionable and dangerous results which might be caused by failure of the control member to function uniformly and properly.

The downward clutch bolt releasing movements of the pivoted control member may be caused by a downward pull,imparted to the control member by a pull rod or pitman 116 which has its upper end pivotally connected with the control member 107 and its lower end pivotally connected with a lever 117 which is fulcrumed intermediate its ends on a horizontal pivot element 118 that is carried by a treadle base 119, Fig. 2. The other i end of the lever 117 is connected by a loose ball and socket or universal joint arrangement 120 with one end of a treadle or actuating lever 121 that is fulcrumed on a horizontal pivot element 122 on the treadle base.

A spring 123 tends to maintain the free end or foot engaging portion of the treadle raised so that the pull rod likewise will be raised as will the pivoted control member 107. However, when the treadle is depressed, the pull rod will be moved downward, thereby pulling the control member 107 downward and permitting projection of the clutch bolt and conseouent clutching of the crank shaft.

to the pulley-fly wheel. This will result in a riveting operation, as has been previously described. As soon as the treadle is released, the springs 123 and 110 will be permitted to function to raise the pivoted control member 1 turning the pulley-fly wheel backward by hand while the treadle is depressed, as a lateral flattened contact face 124 on the outer end portion of the projected clutch bolt will be engaged by one of the shoulders 105 on the adjacent end ofthe pulley-fly wheel and the crank shaft then may be turned backward by hand.

Another beneficial feature of the improved machine resides in the provision of the improved treadle actuated clutch control member hereinbefore described. whereby but relatively slight movement of the treadle by the foot is required to effect the requisite operation of the clutch control member. Also, the treadle base is separate from the base of the machine and the treadle and its connections with the control member are such that the treadle can be disposed in the position most convenient to the operator when handling different kinds and shapes of work.

Moreover, the treadle in its raised position is closer to the floor than is usual so that the operator does not have to raise his foot as high as is usual but is enabled to actuate the treadle with his foot in a comfortable position. This tends to speed up production and together with the remaining features of convenience just enumerated, will aid in reducing to a minimum the labor and fatigue of the operator who ordinarily will actuate the treadle several thousand times during aworking day.

The features of adjustment of the machine permit the most desirable disposition of the work for the convenient and expeditious application oi rivets thereto by the use of the machine under the control of and when actuated by a workman. For example, the swiveling of the column in the base permits adjustment of the machine to accommodate the work which is of advantage at times, as for example, when pieces of work which are large and heavy or difficult to handle are to be riveted.

It is thought that many other features of advantage of the improved machine will be understood from the description that has just been given of the specific construction of a practical embodiment of the invention and of the operation thereof.

any modifications and adaptations of the particular embodiment of the invention herein described may be provided and the features of the invention may be modified as to combination, construction and arrangement according to various conditions of service and requirements without departing from the spirit and scope of the invention as set out in the appended claims.

I claim:

1. A rivet setting machine comprising a base, a column swivelly connected with and supported by said base, rivet applying means supported on said column and driving mechanism for said means also carried by said column.

2. A rivet setting machine comprising a base, an upstanding column supported by the base and connected with the latter for angular adjustment about a vertical axis, a. head on said column, rivet setting means carried by said head and column for angular adjustment with the column about said vertical axis and driving means for said setting means carried by said column.

8. A rivet setting machine comprising asupporting column, a lateral bracket carried by said column, a head on said column, cooperative rivet setting tools respectively carried by said bracket and said head, and means connecting said head and said column for holding the head on the column while permitting said head to rock on the column under stress occasioned by the interposition of a solid rivet or other obstruction between said tools.

4-. A rivet setting machine comprising asu porting column having a Hat supporting top surface, a bracket extending laterally from the column, a head having a flat bottom surface resting on the supporting top surface of the column, cooperating tools respectively carried by the bracket and the head, keys disposed between said head and said colunm and extending at right angles with each other for preventing horizontal displacement of the head on the column, one of said keys being formed to permit the head to rock on the column when a solid obstruction is interposet between said tools during the working stroke, and resilient means holding said head on the column and resisting said rocking movement of the head.

In a rivet setting machine, asuppcrting column, a head resting on said column, cooperative rivet applying devices carried by said head and said column, springs resiliently holding said head down on said column, and

a bearing element between said head and said column on which said head may rock against the action of said springs when an unyielding obstruction is interposed between said rivet applying devices.

6. In a rivet setting machine having an anvil againstwhich the ends of rivets are to be driven, rivet driving means comprising a vertically disposed solid one-piece driver located above said anvil, a yoke to which the upper end of the driver is :cclu'ed rigidly but detachably, a guide above the yoke and having its lower end secured rigidly but detachably to the yoke. means for supporting the driver, yoke and guide for rccipi location as a unit toward and "from the anvil to effect successive rivet setting operations. and driving means engaging said yoke to cause said reciprocations of said unit.

'7. In a rivet setting machine having an anvil against which the ends of: rivets are to be driven, rivet driving means comprising a vertically disposed solid one-piece driver located above said anvil, a yoke to which the upper end of the driver is secured rigidly but detachably, a. guide above the yoke and having its lower end secured rigidly but detach ably to the yoke, means for supporting the driver, yoke and guide for reciprocation as a unit toward and from the anvil to effect successive rivet setting operations, and driving means engaging said yoke to cause said reciprocations of said unit, said driving means comprising a crank shaft having an arm haying a driving connection with the yoke, said crank arm being removable to permit crank arms of different lengths to be used selectively to vary the amplitude of the driving strokes of the driver.

8. In a rivet setting machine, a base, a column upstand ng from the base, a head on the column, cooperative rivet setting means carried by said column and said head, a control member carried by said head for controlling th periodicity of the operations of said rivet setting means, a treadle base separate from said machine base, a treadle fulcrumed on said treadle base, a link connected at one end with said control member for actuating the latter, and an intermediate lever rulcrumed on the treadle base, said intermediate lever having one end connected With said link and having a universal connection at its opposite end with said treadle, whereby a relatively short stroke of said treadle will eii'ect an operating movementof said control member.

9. In a rivet setting machine, abase, a

column upstanding from the base, a head on the column, cooperative rivet setting means carried by said column and said head, a control member carried by said head for controlling the periodicity of the operations of said rivet setting; means, a treadle base separate from said machine base, a treadle fulcrumed on said treadle base, a link connected at one end with said control member for actuatin; the latter, an intermediate lever fulcrumed on the treadle base, said intermediate lever having one end connected with said link and having a universal connection at its 0pposite end with saidtreadle, and a spring tending to maintain the treadle raised, said treadle and the base being; formed to locate said treadle relatively close to the supporting floor when the treadle is raised.

Signed at Forestville, C0nn., this 21st day of June, 1929.

FRANK R. ALFORD. 

